DOI: https://doi.org/10.55373/mjchem.v25i3.251

Keywords: Photonic Crystals; metallo-dielectric; SMMA@Ag-Cu; core shell; Surface Enhanced Raman Scattering

Abstract

Photonic crystals (PCs) have great photon interaction with their periodic structure to create fascinating optical properties. Furthermore, when incorporating PCs with Ag-Cu alloy nano- particles (NPs) in a core-shell structures it has unique linear optical properties that give great enhancements in electromagnetic field in the form of 3D- metallodielectric photonic crystals (MDPCs). However, silver and copper alloy NPs are not widely studied due to their unique localised surface plasmonic resonance (LSPR). Copper alone has a low stability and high tendency to oxidise, thus, silver was used to stabilise the interaction. In this research, combining both LSPR of Ag-Cu NPs and photonic resonance of PCs can create a substrate with high sensitivity towards light. By taking the approach of green sustainability, surfactant free-emulsion copolymerisation reaction was conducted. Copolymer was synthesised in the absence of emulsifiers and toxic solvent, while Ag-Cu NPs obtained from reduction of sodium borohydride. A polyethylene imine (PEI) linker was used to correlate between alloy NPs and copolymers. The UV-vis analysis showed the resulted core shell structure that provided spectrum with a sharp peak at 291 nm and under transmittance electron microscope (TEM) analysis, alloy NPs was strongly held on the spherical ball of copolymer with diameter of 450 nm indicating the successfulness combination of these two materials. In short, this synthesised substrate gave high potential and possibilities to be used as a substrate in surfaced enhanced Raman scattering (SERS).